The Future of Another Timeline

I liked this book, I recommend it and I plan to read others by the author. I have enjoyed her science writing and she is skilled at fiction as well.
Time travel is part of the culture in this book and has been for thousands of years, it's sort of treated as a natural resource. I liked the idea that history was like Wikipedia and is constantly being updated.
If you're sensitive about politics and social issues being mixed into your fiction, reading the book might be a little stressful.

There were two things I didn't like, one is a spoiler.
The non-spoiler is that there is way too much smoking in this book. I'm a little sensitive to this because both my parents were heavy smokers and our house constantly stunk of tobacco.
I blame their smoking on my moms early death and some birth defects that I have.
Whenever I see a character smoking in movies, shows or books, it tells me two things about the character.
One is that they are stupid and the other is that they smell bad.
I doubt that either of these was the authors goal.

Now the spoilery one
It was a big surprise to discover the relationship between the two main narrators.That part was intriguing and well written.But that one of them was also a serial killer was not helpful in telling the story.I don't think this contributed to the characters or the plot.I came away with the idea that all groups of teenagers have at some point killed a person and covered up the crime.

If you like time travel stories, you should read this.
Also, the first place I would visit if I had a time machine is the 1893 Columbian Exposition in Chicago.
I thought that before reading the book and it just reinforced that desire.